The paper introduces an improved retrievable eccentric wedge about its sidetracking method, technological measures and the efficiency. Compared with the traditional one, this eccentric wedge has the advantages of fast sidetracking, inclined coring, no accident threat, no influence on subsequent wire-line core drilling, no specific reaming process and reuse of the eccentric wedge, by which the technical difficulties of bit burning were solved with sidetracking for ZK901 in hard rocks.